Revenue from External Customers and Asset, by Geographical Areas (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Assets	$ 1,602,741	$ 1,974,468	$ 3,271,197
Total revenues	2,963,252	3,278,420	3,157,796
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Assets	1,567,933	1,930,676	3,204,283
Total revenues	2,911,613	3,209,736	3,075,387
Mexico [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Assets	31,415	38,898	59,841
Total revenues	50,927	63,803	72,202
Canada [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Assets	3,393	4,894	7,073
Total revenues	$ 712	$ 4,881	$ 10,207